Calipers



A. W. HOFFMAN.

CALIPERS. APPLICATION FILED FEB.10,1921.

1,420,700. pmmdzrugm, 1922.

A. W. HOFFMAN.

lCALIPERS.

APPLICATION manas. 1o, 192|.

' Patented June 27, 1922..

`2 SHEETS-SHEET 2- zi zig-jaa .(,iIiFiaFin w, HOFFMAN, oF NEW YORK, N. Y.

. CALIPERS.

To all whom t may concermV Be it known that I, ALFRED W. HOFFMAN, a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain' new, and useful'mprovements injCalipers,

of which the'following is a full, clear, and

exact specification.

This invention `relates tol calipers and has .for one of its objects to provide a measuring instrument of this kik-nd bywhich an external diameter maybe determined from a corresponding internal diameter, or an, internal diameter determined from a corresponding external diameter. I p

The invention contemplates the provision ot parallel members adapted to be moved! toward and away froineachother in paral-v lelism and having a pair of arms at one end for making external measurements, and a Y pair of arms at the other end Vfor mal;-

ing corresponding internal measurements.

Thus, if one piece of work is to'beimade to' fit within another, it is only necessary to set the calipers so that its internally Ineasel uring arms ft the outer, piece of work, and` the external measuring arms at the other end:

of the instrumentpwill be set for the proper external measurement o'l' theinner piece 'of work. In the same way, theproper internal'Y `diameter of an outer piece .of work may be;v

determined i from :the measurement of the'` external diametery of an inner piece of ,work

, over which said outer piece'of workis to be;`

made to lit. l f a Another vobject isv to provide improved means for maintaining the 'parallel inembers of ther calipers .in parallelism during adjustments. improved means forA adjusting said parallel members, and another Objectis to provide for locking said members in any desired adjustin-lenig.V Other objects will appear as the description'proceeds. l' g` Theinvention Awill be first liereifnafteidescribed; in connection with the acconzipanys ing drawings `which'constitute part ofg this specification, andthen more specifically `dened in the claims atV the end of the description. Y

In the accompanying drawings, wherein Appiicationiiiea .February 1o, 1921. semi N6. 443,813.7.

A further object is tol provide Y lSpecification of Letters atent. n Patented'Jlllle l similar reference characters arefiused to designate corresponding' parts throughoutthe several views :l 'V

uring arms are in contact with,` one ,another and adapted to measure the smallest Vinternal diametenwhile the external arms are spacedvk apart a distance 'corresponding totlie diam Figure 1 isa front elevation of a pairot calipers constructedAV substantially accord-V` ance with this invention and shown ,in col#` lapsed `positions where rv`the 'internally meas eter of said contacting internally measur.

ing arms.

Figure 2 is ment. i

the calipers set to measure the internal d and external diameters of -intertting pieces..of

work. .s i Y.

Figure 4 is; a detailed, front view of the lower portion `of the -calipers,fshovvfing a modied form-of guidingand lockinglde'-`v vice. e

in Figure 4.4

a side elevationof the instru# Figure 5 is asideviewof ltheparts shown tive viewsv` of different`v` forms x ofinternally have central gears 10,*11 andf12w ich are of the same` diameter y,anch intermeshwith:

one another.` Thefmiddlescrew'has en.- largedmilled flangesjl?) atthe sides of its geark 11, saidv flanges overlapping the.V gears 10 and 12 of the other; screws and serving to maintain them .inproper alignmentj VSaid milled flangesf 13 alsoserve as`OperatingdA at different V distances apart.y Itl will :be

.noted that the gearsand milledfanges O the screws arefV arranged `between the par# `1 means for rotating all .off-fthe..screws'fsiniul` i' `taneously to .adjust ,the members l, and 2 alle l members 1v and ofthe instrumen@ and that the inner edges of said members are cut away, as at 14, to clear said parts when the calipers are collapsed, as shown in Figurel.

A transverse bar 15 is arranged in groovesv 16 of the members 1 andf2 for preventing one member from getting'out'of parallelism with the other during adjustment. Brackets 17 are secured to said members to bridge the cross bar 15 for retaining it in its grooves 16, and clamps 18 arecarried by said brackets for locking the calipers in any set position. In practice, one of the clamps 18 is kept inclamping position so as to hold one end of the cross bar 15 rigidly in engagement with one of the parallel members of the calipers while the other clamp is in released position during adjustments, as shown in Figure 1. After the desired adjustment has been reached, the second clamp is operated, as shown in Figure 3, to hold said adjustment. l

l Internally measuring arms 19 are carried by end piecesr20 which are detachably vsecured to corresponding ends of the parallel members 1 and 2 in any suitable manner, as

by the ltongues 21 on said end pieces engaging corresponding' sockets in said parallel membersvand retained in place by. set screws 22. Externally measuring arms 25 are detachably secured to the other ends of said parallel members in the same manner, as by tongues 26 locked by set screws 27. Said arms 25 are preferably bowed and tapered to their ends 24 which are adapted to engage the outside of a piece of work 30, Figure 3, while the arms 19 are adapted to lit the internal diameter of the socket of a piece of work 23 which is adapted to fit over the piece of VVwork 30. .Co-acting scales or'verniers 28 and 29 are secured, respectively, to the parallel members 1 and2.for measuring the distance between said members. Any other suitable measuring scales may be substituted, if desired.

VvAs shown in Fig. 6 the internally measuring arms 19 may be semi-cylindrical in cross section, having straight contacting faces 31, so that when .said arms are brought into contactv with each other, as indicated in Figure 1, they will together form a cylindrical rod of the smallest desired diameter capable of measuring a socket of minimum size. The internally measuring arms may be made inany other suitable form, as long as they together form a cylindrical rod when brought into contact with each other. As shown in Figure 7, internally measuring arms190 are provided respectively with a V-V shaped groove 32 and an intertting V- shaped ribv 33. In Figure 8, internally measuring arms 191 have an interfittingA groove 34 and rib v35, respectively, of another form.v

As shown'in Figures 4 and 5, a guiding bar 150 may be permanently fastened to one of the said members toward and away from each other, a cross barextendingrfrom one member across the other, there being a groove in said last mentioned member' to lit said cross kbar for maintaining said members in parallelism during adjustment, and a bracket bridging said groove for retaining the cross bar therein.

2. In calipers, the combination with parallel members, of means for adjusting said members toward and away from each other, a cross bar extending from one member across the other, there being a groove ink saidlast mentioned member to fit said'cross bar for maintaining said members inparallelism during adjustment, a bracket bridging said groove, and a clampy carried by ,said bracket for engagingthe crossjbar to lock the calipers inadjusted position. Y

3. In calipers, the combination with parallel members having notches in their Vadj acent faces, of a plurality of screws for adjusting said members toward and away from each other, and intermeshing gears of the `same size fast on said screws for causing them to rotate in unison, said gears being arranged in said notches when the parallel members are brought together. l l

L4. I n calipers, the combination with parallelmembers, of three screws for adj usting said members toward ,and away from each other, intermeshing gears of the same size fast on said screws vfor causing them to rotate in unison, and flanges on the middle screw'extending at both sides of its gear and overlapping the intermeshing gears of the adjacent screws for maintaining said gears in alignment. i n

5. In calipers, the combination with parallel members, ofthree screws for adjusting said members toward and away from each other, intermeshing gears of the same size fast on said screws for causing them to rotate in unison, and flanges on the middle screw extending at both sides of its' gear and' overlapping the intermeshing gears of the adjacent screws forl maintaining said gears in alignment,the peripheries of said flanges being roughened for the purpose specified. 6. In calipers, the combination with parallel members, ofa plurality o-fscrews Y away from each other, and intermeshing gears of the same size fast on said screws for causing them to rotate in unison, and

flanges on one screw extending at the sides of its gear and oyerlappingthe intermeshinggear of the adJaeent screw for maintaining said gears in alignment, said gears and v flanges being arranged between'l the parallelv members of the calipers, the latter having recesses to clearsaid parts.

In testimony Vwhereof I have signed my name to this specication.

ALFRED W. HOFFMAN. s i 

